[单选题]
The diagram below shows a protein composed o prw fd; kb)oh(42oc7hf three polypeptide chains, eachi ln7fzf0ex;yz;t0*+f5x d tw chain contains 20 amino acids.
we x f f;d*txzt70y 0il+zf;5n
How many water molecules would be released in the synthesis of one of these chains?